At Home on the Range

Devil in the Mountain: A Search for the Origin of the
Andes. Simon Lamb. xii + 335 pp. Princeton University Press,
2004. $29.95.

Geologists are, by nature, passionate about mountain ranges. We are
fascinated by their beauty and become engrossed in their personal
histories. Our relationship with an individual range tends to last
years or decades. In short, we become quite attached.

In the pantheon of the world's mountain belts, two are particularly
revered by geologists. One is the Himalayan Tibetan system, the
highest and largest range on the surface of the Earth, which
resulted from a colossal collision between the continents of India
and Asia. The other is the Andes of South America, the
second-highest range overall and the highest in the Western
Hemisphere. It was formed in a quite different and less well
understood manner, as the cold, relatively dense tectonic plate
beneath the eastern Pacific Ocean—the Nazca
Plate—slipped beneath the South American continent.

The Andes have long been known as the home of great volcanoes, but
only in the past two decades have geologists realized that most of
the elevation of these mountains is due not to a piling up of lava
but to deformation and crustal thickening. A flurry of efforts in
the 1980s attempted to show that the Andes must have been formed as
the result of a collision between South America and some phantom
continental fragment or oceanic plateau. These endeavors failed
utterly, and the exact causes of mountain building in the Andes have
remained enigmatic.

It is this enigma that drew Simon Lamb to the Andes in the late
1980s, and Devil in the Mountain is a very personal account
of his quest to understand this great mountain range. Lamb's book is
in equal measures a collection of personal anecdotes about his
fieldwork, mostly in the Bolivian Andes, and an attempt to describe
to the layperson his conclusions about how the mountains formed.

Lamb largely succeeds in describing both the scientific work and the
personal motivation of a field geologist in terms that a
nonscientist can understand. His prose is lively and for the most
part free of jargon. His tales of adventures during individual field
campaigns engage readers in a way that a straight science text could
not. Most important, he describes particularly well the process by
which a field geologist interprets the Earth. Novices have little
idea why a geologist chooses to measure one thing but not another.
Lamb sheds light on these decisions by leading the reader clearly
through the iterative process of making observations and posing
hypotheses to guide future investigations.

In an effort to make the book accessible, Lamb uses a plethora of
metaphors and draws analogies to common objects. The Andes are
variously compared to, among other things, the knee of a crouching
athlete, a "fudge cake" and a saucepan of hot syrup. These
efforts are largely successful, but sometimes they backfire, as when
he mixes metaphors or draws analogies to objects that will be
familiar only to British readers.

In the anecdotal parts of the book, unsubstantiated rumors sometimes
slip through; for example, Lamb uncritically repeats the allegation
that the American ambassador was behind a decision of the Bolivian
government to reduce inflation by cutting all government
expenditure, including funding for the Geological Survey. Also, Lamb
relates some events incorrectly. For example, he credits a meeting
at Cornell with having been the impetus for a German-funded group to
lay out a line of seismometers across the Central Andes, but in
fact, the German efforts were planned and funded long before the
Cornell meeting took place.

Any geologist who has worked in the Andes, as I have, will find it
difficult to be entirely objective about the book. Lamb uses the
personal pronoun "I" with abandon—often at least 10
times in a single paragraph—even when relating ideas,
observations and concepts shared by dozens of Andean geologists. He
tries to head off criticism for this style by acknowledging in the
preface that many geologists have contributed to our understanding
of the Andes. Nonetheless, readers would do well to remember that
Lamb is describing a journey of personal discovery rather than
completely original scientific findings.

Eight pages of recommendations for "Further Reading" are
furnished at the back of the book. This material gives readers
access to a subset of the most important publications on the
subject, including not a few of Lamb's own. He and his colleagues
have published many original, influential and occasionally
controversial journal articles, which have been paraphrased and
presented in the latter part of the book as the explanation for
Central Andean geology. To briefly summarize, Lamb suggests that
climate change in the Late Cenozoic era was ultimately responsible
for the unusual width and height of the central Andes. He proposes
that the onset of hyperaridity along the west coast of South America
reduced the supply of the water-saturated sediments that lubricated
the interface between the tectonic plates. Thus higher stress was
transmitted across the interface, producing a greater amount of
deformation in western South America.

Lamb ends the book with an anecdote making the point that it is
important to distinguish between pseudoscience and real science.
However, he fails to acknowledge the uncertainty that continues to
surround deeper and more serious questions about the origin of the
Central Andes. Because uncertainty, which lies at the heart of many
conundrums facing society, is a difficult concept for nonscientists
to grasp, the book might have served nontechnical readers better by
emphasizing it. Also, because Lamb's group from Oxford did not
involve South American geoscientists in their research after the
occasion of Lamb's initial trip, the book may help to perpetuate an
unfortunate stereotype; I hope readers will not be left with the
impression that there are no geologists of note in that vast continent.

Most of these criticisms will matter little to laypeople, and for them,
this book does a fine job of explaining how and why field geologists go
about their business. Having had many similar experiences, I was
impressed with the honesty with which Lamb relates his personal
reactions, concerns and miscues. Although most geologists would not
admit to being repeatedly "drenched in sweat" from anxiety,
the fact remains that our fieldwork is carried out in remote areas under
conditions of considerable risk, and not a few of us have felt the
trepidation he describes so graphically. Likewise, many of us will smile
in recognition at Lamb's moments of intellectual and physical triumph,
and at the glimpses of the sublime so common in remote areas. In that
sense, Lamb has captured the essence of what it is to be a field
geologist.—Richard W. Allmendinger, Earth and Atmospheric
Sciences, Cornell University